1. Pulse mass measles vaccination across age cohorts;Ager;Proc. Natl. Acad. Sci. USA,1993
2. D. Bainov, P. Simeonov, Impulsive differential equations: periodic solutions and applications, Pitman Monographs and Surveys in Pure and Applied Mathematics, vol. 66, 1993.
3. The history of the vedalia beetle importation to California and its impact on the development of biological control;Caltagirone;Ann. Rev. Entomol.,1989
4. The existence and uniqueness of limit cycles in general predator–prey differential equations;Chen;Chinese Sci. Bull.,1984
5. Biological Control of Insect Pests and Weeds;DeBach,1964